ROM vs computer storage

ROM and computer storage both are nouns.

Word	Noun	Adjective	Verb	Adverb
ROM	Yes	No	No	No
computer storage	Yes	No	No	No

As nouns, computer storage is a hypernym of ROM; that is, computer storage is a word with a broader meaning than ROM:

ROM: (computer science) memory whose contents can be accessed and read but cannot be changed
computer storage: an electronic memory device

Other hypernyms of ROM include computer memory, memory, memory board, storage, store.

ROM (noun)	computer storage (noun)
(computer science) memory whose contents can be accessed and read but cannot be changed	an electronic memory device